Display panel

ABSTRACT

A display panel includes a first substrate, an electrode layer, and a display medium layer. The electrode layer is disposed on the first substrate. The display medium layer is disposed on the electrode layer and includes a filler and liquid crystal capsules. The liquid crystal capsules are distributed in the filler, and the filler has a birefringence difference Δn in a range from 0.02 to 0.175.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a Divisional of the application Ser. No.16/840,494, filed on Apr. 6, 2020, now U.S. Pat. No. 11,092,838, andthis application claims priority to Taiwan Application Serial Number108127621, filed Aug. 2, 2019, the entire contents of which are herebyincorporated herein by reference in their entireties.

BACKGROUND Technical Field

The present disclosure relates to a display panel.

Description of Related Art

Among various electronic products of household electrical appliances,liquid crystal display devices applied with thin-film transistors (TFTs)have been widely used. The thin-film transistor type liquid crystaldisplay device is mainly composed of a thin-film transistor arraysubstrate, a color filter array substrate and a liquid crystal layer, inwhich the thin-film transistor array includes a plurality of thin-filmtransistors arranged in array, and each of the thin-film transistors isprovided with a pixel electrode correspondingly.

When the pixel electrode is driven through the thin-film transistor, thepixel electrode turns liquid crystal molecules in the liquid crystallayer, thereby controlling the optical chirality of the liquid crystallayer for the light beam. In this regard, the ingredients of the liquidcrystal layer affects the display quality of the liquid crystal display.Therefore, how to enhance the display quality of the liquid crystaldisplay by adjusting the ingredients of the liquid crystal layer hasbecome one of the important research and development direction in thefield.

SUMMARY

An embodiment of the present disclosure is to provide a display panel,which includes a first substrate, an electrode layer and a displaymedium layer. The electrode layer is disposed on the first substrate.The display medium layer is disposed on the electrode layer, andincludes a filler and a plurality of liquid crystal capsules, in whichthe liquid crystal capsules are distributed in the filler, and thefiller has a birefringence difference Δn in a range from 0.02 to 0.175.

In some embodiments, the display panel further includes a secondsubstrate. The second substrate is disposed on the display medium layer,and each of the first substrate and the second substrate is flexible.

In some embodiments, the display panel further includes a plurality ofspacers disposed between the first substrate and the second substrate,in which the second substrate is formed by curing at least one monomeradded into the display medium layer, and at least a portion of the curedsecond substrate is disposed between the spacers.

In some embodiments, the electrode layer includes a plurality ofstereoscopic electrodes. Each of the stereoscopic electrodes includes aprotruding structure and an electrode pad, in which the protrudingstructure protrudes from the first substrate toward the display mediumlayer, the electrode pad is disposed on the protruding structure, and athickness of the electrode pad is in a range from 300 nm to 700 nm.

In some embodiments, each of the liquid crystal capsules includes acapsule film and at least one liquid crystal molecule, and the capsulefilm covers the liquid crystal molecule, in which the liquid crystalmolecule is a rod-shaped structure or a disc-shaped structure.

In some embodiments, the liquid crystal molecule is the disc-shapedstructure, and the capsule film is an optical thermal adhesive formed ofat least one monomer having a stick-shaped structure.

In some embodiments, the first substrate includes a transparentsubstrate, an array layer, and a color filter layer, the transparentsubstrate is flexible, and the array layer is disposed between thetransparent substrate and the color filter layer.

In some embodiments, a short axial refractive index n_(⊥) of the filleris in a range from 1.45 to 1.5, and a long axial refractive index n_(∥)is in a range from 1.5 to 1.55.

An embodiment of the present disclosure is to provide a display panel,which includes a first substrate, an electrode layer and a displaymedium layer. The electrode layer is disposed on the first substrate.The display medium layer is disposed on the electrode layer, andincludes a filler and a plurality of liquid crystal capsules, in whichthe liquid crystal capsules are distributed in the filler, and amaterial of the filler at least includes at least one 1,4-cyclohexylenederivative, at least one 1,4-phenyl derivative, at least one 1,3-indenylderivative or combinations thereof, in which the chemical formula of1,4-cyclohexylene derivative is

the chemical formula of 1,4-phenyl derivative is

and the chemical formula of 1,3-indenyl derivative is

In some embodiments, the display medium layer further includes asurfactant uniformly mixed and distributed in the filler.

According to the aforementioned configuration, the birefringencedifference Δn of the filler is implemented to be in a range from 0.02 to0.175 by adjusting the material of the filler. As a result, thebirefringence difference Δn of the filler can be matched with therefractive index of the electrode layer, thereby avoiding light leakageof the display panel in a dark state so as to increase contrast of thedisplay panel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic side view of a display panel according to a firstembodiment of the present disclosure.

FIG. 1B to FIG. 1D are schematic top views of the stereoscopic electrodeof FIG. 1A in different embodiments, respectively.

FIG. 2A to FIG. 2D are schematic side views of the display panel of FIG.1A at different stages in the manufacturing process, respectively.

FIG. 3A to FIG. 3C are schematic side views of the electrode layer indifferent embodiments, respectively.

FIG. 4 is a schematic side view of a display panel according to a secondembodiment of the present disclosure.

FIG. 5A to FIG. 5D are schematic side views of the display panel of FIG.4 at different stages in the manufacturing process, respectively.

DETAILED DESCRIPTION

In the following detailed description, for purposes of explanation,numerous specific details are set forth in order to provide a thoroughunderstanding of the disclosed embodiments. It will be apparent,however, that one or more embodiments may be practiced without thesespecific details. In other words, in some embodiments of the presentinvention, these practical details are not necessary. Moreover, somewell-known structures and devices are schematically depicted in order tosimplify the drawings.

In the present disclosure, it is comprehensible that terms such asfirst, second, and third are used to describe various components orareas. The terms are used for identifying single component or area.Therefore, the following first component or area may also be called asthe second component or area without departing from the intention of thepresent disclosure. “Approximately” or “substantially” used hereinincludes an average value within an acceptable deviation range and thedescribed value. For example, “approximately” or “substantially” mayrepresent being within one or more standard deviations of the describedvalue, or within ±30%, ±20%, ±10%, or ±5%.

Reference is made to FIG. 1A. FIG. 1A is a schematic side view of adisplay panel 100A according to a first embodiment of the presentdisclosure. The display panel 100A includes a first substrate 110, anelectrode layer 120, a display medium layer 130, spacers 140, and asecond substrate 150.

The first substrate 110 may include a transparent substrate 112, anarray layer 114, and a color filter layer 116, in which the array layer114 and the color filter layer 116 are sequentially formed on thetransparent substrate 112, that is, the array layer 114 is locatedbetween the transparent substrate 112 and the color filter layer 116.

The transparent substrate 112 is flexible. For example, the transparentsubstrate 112 may be a polyimide (PI) substrate. The array layer 114 mayinclude an array arranged by a plurality of thin-film transistors (notshown). The color filter layer 116 may include a light-shielding layer(not shown) and a plurality of color resist layers (not shown) withdifferent colors, such as a red color resist layer, a green color resistlayer, and a blue color resist layer, in which the light-shielding layermay be formed as a black matrix, thereby defining the forming positionof each of the color resist layers. With this configuration, theconfiguration of color filter on array (COA) can be implemented on thefirst substrate 110 with a plurality of pixel areas therein.

In addition, the first substrate 110 may further include a protectivelayer 118, in which the protective layer 118 is disposed on the colorfilter layer 116, so as to prevent an upper surface of the color filterlayer 116 from being damaged. The protective layer 118 may have contactholes (not shown) in conjunction with the color resist layer of thecolor filter layer 116, such that the thin-film transistors of the arraylayer 114 can be connected to layers formed on the protective layer 118through the contact holes.

The electrode layer 120 is disposed on the protective layer 118 of thefirst substrate 110, and the display medium layer 130 is disposed on theelectrode layer 120. The electrode layer 120 may include a plurality ofstereoscopic electrodes 122, and each of the stereoscopic electrodes 122includes a protruding structure 124 and an electrode pad 126. Theprotruding structure 124 can protrude from the first substrate 110toward the display medium layer 130. In some embodiments, the protrudingstructure 124 and the protective layer 118 of the first substrate 110can be formed in the same mask process, for example, a photoresist layercan first be formed on the color filter layer 116, and then an exposureis performed on the photoresist layer by using a half-tone mask, therebyforming the protruding structure 124 and the protective layer 118 whichare connected to each other after lithography. However, the presentdisclosure is not limited in this regard. In other embodiments, theprotruding structure 124 and the protective layer 118 can be formedsequentially. The electrode pad 126 is disposed on the protrudingstructure 124 and is conformal to the protruding appearance of theprotruding structure 124. The electrode pad 126 can be connected to thethin-film transistor of the array layer 114 through the contact hole,such that the electrode pad 126 can be driven by the thin-filmtransistor of the array layer 114. In other words, the stereoscopicelectrode 122 can be used as a pixel electrode, which can generate anelectric field by coupling and change the optical chirality of thedisplay medium layer 130.

In some embodiments, a thickness T1 of the electrode pad 126 may be in arange from 300 nm to 700 nm. When a material of the electrode pad 126includes metal, the electrode pad 126 having such a thickness may have arefractive index. For example, when the material of the electrode pad126 is silver, the electrode pad 126 has a refractive index in a rangefrom 0.1 to 0.2. In addition, the material of the electrode pad 126 mayalso include a transparent conductive material, such as indium tinoxide, indium zinc oxide, zinc oxide, indium gallium zinc oxide, orother suitable materials. With this configuration, the opticalproperties of the electrode pad 126 can be matched with the opticalproperties of the display medium layer 130, which will be discussed inthe following descriptions.

In some embodiments, a thickness T2 of the protruding structure 124 maybe in a range from 1 μm to 4 μm, or in a range from 1 μm to 3 μm. Sincea shape of the protruding structure 124 is related to the electricalfield lines coupled by the electrode pad 126, the electrical field linescoupled by the electrode pad 126 can be adjusted by adjusting thethickness T2 of the protruding structure 124 in order to reduceoperating voltage for driving the electrode pad 126. In addition, foreach pair of adjacent electrode pads 126, different voltages, such as apositive voltage and a negative voltage, can be applied thereto when theimage is displayed on the display panel 100A.

The protruding shape of the stereoscopic electrode 122 in FIG. 1A can bepresented as a plurality of strip-shaped patterns in a top viewing angle(i.e., when the display panel 100A is viewed from the top), and thestrip-shaped patterns may have large or small angles therebetween indifferent directions. For example, references are made to FIG. 1B, FIG.1C, and FIG. 1D, which are schematic top views of the stereoscopicelectrode 122 of FIG. 1A in different embodiments, respectively.

As shown in FIG. 1B, FIG. 1C, and FIG. 1D, the array layer 114 mayfurther include scan lines SL, data lines DL, and a thin-film transistorTFT, in which the scan lines SL and the data lines DL can be interlacedto form a pixel area PA. The thin-film transistor TFT is disposed in thepixel area PA, in which the gate of the thin-film transistor TFT can beconnected to the scan line SL, and the source of the thin-filmtransistor TFT can be connected to the data line DL. The stereoscopicelectrode 122 may be located in the pixel area PA and electricallyconnected to the drain of the thin-film transistor TFT for being used asa pixel electrode. The protruding shape of the stereoscopic electrodes122 can be designed as a strip-shaped pattern, a line width L of each ofthe stereoscopic electrodes 122 can be in a range from 4 μm to 6 μm, anda line spacing P between each of the adjacent stereoscopic electrodes122 may be in a range from 7 μm to 9 μm. The configuration of thestereoscopic electrode 122 in the pixel area PA is not limited in thisregard. In other embodiments, the protruding shape of the stereoscopicelectrode 122 may be designed to have a strip-shaped pattern of otherstyles.

Reference is made back to FIG. 1A. The display medium layer 130 mayinclude a filler 132 and liquid crystal capsules 134, in which theliquid crystal capsules 134 are uniformly mixed and distributed in thefiller 132. In some embodiments, a filling thickness of the filler 132may be in a range from 2 μm to 4 μm, or in a range from 2 μm to 3 μm,and a diameter of each of the liquid crystal capsules 134 may be in arange from 100 nm to 320 nm.

A birefringence difference Δn of the filler 132 may be in a range from0.02 to 0.175. In this way, the birefringence difference Δn of thefiller 132 can be matched with the refractive index of the electrode pad126, thereby avoiding light leakage of the display panel 100A in a darkstate so as to enhance contrast of the display panel 100A.

The filler 132 having such a birefringence difference Δn can be achievedby adjusting its material configuration. Specifically, a material of thefiller 132 may at least include 1,4-cyclohexylene derivative, 1,4-phenylderivative, 1,3-indenyl derivative, 4,4′-biphenyl derivative, orcombinations thereof, in which the chemical formula of 1,4-cyclohexylenederivative is

the chemical formula of 1,4-phenyl derivative is

the chemical formula of 1,3-indenyl derivative is

and the chemical formula of 4,4′-biphenyl derivative is

In this regard, the birefringence difference of 1,4-cyclohexylenederivative is in a range from 0.02 to 0.054, the birefringencedifference of 1,4-phenyl derivative is in a range from 0.097 to 0.106,the birefringence difference of 1,3-indenyl derivative can beapproximately 0.085, and the birefringence difference of 4,4′-biphenylderivative can be approximately 0.175. Since the minimum birefringencedifference among 1,4-cyclohexylene derivative, 1,4-phenyl derivative,1,3-indenyl derivative, and 4,4′-biphenyl derivative can beapproximately 0.02 and the maximum birefringence difference among themcan be approximately 0.175, the birefringence difference Δn of thefiller 132 can be adjusted to be in a range from 0.02 to 0.175 byadjusting the proportion of these materials in the filler 132.Furthermore, a short axial refractive index n_(⊥) of the filler 132 canbe adjusted to be in a range from 1.45 to 1.5, and a long axialrefractive index n ii of the filler 132 can be adjusted to be in a rangefrom 1.5 to 1.55. Alternatively, 4,4′-biphenyl derivative can beomitted, such that the birefringence difference Δn of the filler 132 canbe adjusted to be in a range from 0.02 to 0.1. In addition, with thisconfiguration, the filler 132 is a mixture.

However, the present disclosure is not limited in this regard. In otherembodiments, other materials can also be mixed into the filler 132 tofurther adjust the birefringence difference Δn of the filler 132. Forexample, the material of the filler 132 may further includecyclohexylene derivative, of which the chemical formula is

in which the terminal group “R” in the chemical formula may be hydrogen,halogen, an alkyl group having 1 to 20 carbon atoms or combinationsthereof, the value “n” in the chemical formula may be an integer from 1to 12, and the “B” in the chemical formula may be cycloalkanes oraromatic hydrocarbons.

In some embodiments, the material of the filler 132 may further include:4-vinyl-4′-propyl-1,1′-bicyclohexane, in which the chemical formula is:

4-allyl-4′-propyl-1,1′-bicyclohexane, in which the chemical formula is:

4-tolyl-4′-vinyl-1,1′-bicyclohexane, in which the chemical formula is:

4-allyl-4′-tolyl-1,1′-bicyclohexane, in which the chemical formula is:

4-pentyl-4′-propyl-1,1′-bicyclohexane, in which the chemical formula is:

4,4′-dipentyl-1,1′-bicyclohexane, in which the chemical formula is:

4-hexyl-4′-pentyl-1,1′-bicyclohexane, in which the chemical formula is:

4-tolyl-4′-propyl-1,1′-bicyclohexane, in which the chemical formula is:

4-[ethyl(cyclopentyl)]-4′-[(trifluoromethoxy)phenyl]-1,1′-bicyclohexane,in which the chemical formula is:

4-heptyl-4′-hexyl-1,1′-bicyclohexane, in which the chemical formula is:

2-heptyl-5-(4-heptylcyclohexyl)tetrahydro-2H-pyran, in which thechemical formula is:

or combinations thereof. In some embodiments, the filler 132 may becomposed of the above materials, in which the content of the4-vinyl-4′-propyl-1,1′-bicyclohexane is 18.44%, the content of the4-allyl-4′-propyl-1,1′-bicyclohexane is 9.31%, the content of the4-tolyl-4′-vinyl-1,1′-bicyclohexane is 9.12%, the content of the4-allyl-4′-tolyl-1,1′-bicyclohexane is 25.66%, the content of the4-pentyl-4′-propyl-1,1-bicyclohexane is 5.28%, the content of the4,4′-dipentyl-1,1′-bicyclohexane is 4.86%, the content of the4-hexyl-4′-pentyl-1,1′-bicyclohexane is 5.12%, the content of the4-tolyl-4′-propyl-1,1′-bicyclohexane is 5.88%, the content of the4-[ethyl(cyclopentyl)]-4′-[(trifluoromethoxy)phenyl]-1,1′-bicyclohexaneis 6.18%, the content of the 4-heptyl-4′-hexyl-1,1′-bicyclohexane is5.30%, and the content of the2-heptyl-5-(4-heptylcyclohexyl)tetrahydro-2H-pyran is 4.86%.

In the condition that the filler 132 is formed by adjusting theproportion of the aforementioned materials, since the aforementionedmaterials are oily substance, they are less likely to react withmoisture. For example, the filler 132 may have a low water-absorbingcharacteristic, thereby preventing the filler 132 from absorbing themoisture in the environment, which affects the reliability of thedisplay panel 100A.

On the other hand, each of the liquid crystal capsules 134 can include acapsule film 136 and liquid crystal molecules 138, and the capsule film136 covers the liquid crystal molecules 138. Although in FIG. 1A, theliquid crystal capsule 134 is illustrated as a capsule film 136 coveringone liquid crystal molecule 138, the present disclosure is not limitedin this regard. In other embodiments, a capsule film 136 can cover morethan one liquid crystal molecule 138.

The liquid crystal molecules 138 can be selected as a rod-shapedstructure or a disk-shaped structure, in which the rod-shaped structurecan be defined by a relationship between its triaxial refractive index,which is nz>nx=ny, and the disk-shaped structure can be defined by arelationship between its triaxial refractive index, which is nx=ny>nz.When the liquid crystal molecules 138 are selected to have a disc-shapedstructure, a surface of the capsule film 136 is an optical thermaladhesive formed by a monomer having a stick-shaped structure, in whichthe stick-shaped structure can be defined by a relationship between itstriaxial refractive index, which is nz>nx=ny, such that the structure ofthe capsule film 136 can match with that of the liquid crystal molecules138 to present better optical properties, for example, the opticalviewing angle can be increased. The birefringence difference, refractiveindex, triaxial refractive index, short axial refractive index, and longaxial refractive index described in the foregoing embodiments aregenerally measured in the visible light band, and are unitless.

In addition, the display medium layer 130 further includes a surfactant139, which is uniformly mixed and distributed in the filler 132. Thesurfactant 139 may include linear chain molecules, in which thestructure of the linear chain molecules may have one end of hydrophilicgroup, such as a hydroxide ion group, and the other end of a hydrophobicgroup, such as an alkane group. In some embodiments, the surfactant 139may at least include non-ionic surfactant, polyoxyethylene derivative,fatty alcohol polyvinyl ether derivative, or combinations thereof, inwhich the chemical formula of polyoxyethylene derivative is:

and the chemical formula of fatty alcohol polyvinyl ether derivative is

By adding the surfactant 139 into the display medium layer 130, theliquid crystal capsules 134 can be more uniformly mixed in the filler132 to prevent the liquid crystal capsules 134 from clustering in apartial area of the filler 132. In some embodiments, the surfactant mayfurther include Surfynol-104H, Surfynol-420, Surfynol-440, SurfynolSE-F, Dynal-360, Dynal-604, Pluronic-10R5, Plu-25R5, Pluronic F127,Pluronic-L44, or combinations thereof.

The spacers 140 can define more than one accommodation spaces betweenthe first substrate 110 and the second substrate 150, thereby preventingthe liquid crystal capsules 134 of the display medium layer 130 frommoving and resulting in a nonuniform distribution. The second substrate150 is disposed on the display medium layer 130 and has transparency andflexibility, for example, the second substrate 150 may be a polyimidesubstrate.

References are again made to FIG. 2A to FIG. 2D, which are schematicside views of the display panel 100A of FIG. 1A at different stages inthe manufacturing process, respectively. As shown in FIG. 2A, a secondsubstrate 150 can first be formed on a first carrier substrate 102, inwhich the first carrier substrate 102 may be a glass substrate. Next,spacers 140 can be formed on the second substrate 150, such that morethan one accommodation spaces are defined on the second substrate 150 bythe spacers 140. In addition, the spacers 140 may be formed in trapezoidshapes with respect to the second substrate 150.

As shown in FIG. 2B, the display medium layer 130 can be filled in theaccommodation spaces defined by the spacers 140 by, for example, a onedrop fill (ODF) manner. In addition, at this stage, a surfactant 139 maybe added into the display medium layer 130.

As shown in FIG. 2C, a first substrate 110 can be formed on a secondcarrier substrate 104, in which the second carrier substrate 104 may bea glass substrate, and the step of forming the first substrate 110includes forming a transparent substrate 112, an array layer 114 and acolor filter layer 116 sequentially. Next, a protective layer 118 and anelectrode layer 120 may be formed on the color filter layer 116sequentially, in which the electrode layer 120 is formed to include aplurality of stereoscopic electrodes 122, and the stereoscopic electrode122 includes protruding structures 124 and electrode pads 126. Asdescribed above, the protective layer 118 and the protruding structure124 can be formed simultaneously or sequentially, which will not berepeated hereinafter. After the protruding structures 124 are formed,contact holes (not shown) may be formed, such that the electrode pads126 formed subsequently can be connected to the thin-film transistors ofthe array layer 114. The step of forming the electrode pad 126 mayinclude a patterning process, for example, a conductive layer may beformed on the protective layer 118 and the protruding structures 124,and the conductive layer can be patterned by exposure and lithography toform electrode pads 126 as shown in FIG. 2C.

As shown in FIG. 2D, the structures shown in FIG. 2B and FIG. 2C can beassembled to form the structure of FIG. 2D, in which the secondsubstrate 150 can be disposed on the first substrate 110, and thespacers 140 may be in inverted-trapezoid shapes with respect to thefirst substrate 110. In this regard, during the assembling, a sealantcan be disposed on the periphery of the first substrate 110 or thesecond substrate 150, and the sealant can be heated or provided withlight to be cured, so as to fix the second substrate 150 to the firstsubstrate 110. In some embodiments, during the assembling, otheradhesive, such as ultraviolet-curing adhesive, can also be coated on thetop surface of the spacers 140 to increase the fixing strength of thesecond substrate 150 to the first substrate 110, and thus preventing thesecond substrate 150 from being separated from the first substrate 110.After the assembling is finished, the second carrier substrate 104 canbe detached from the first substrate 110, and the first carriersubstrate 102 can also be detached from the second substrate 150, so asto obtain a display panel 100A as shown in FIG. 1A. In addition, afterthe display panel 100A is obtained, polarizers (not shown) can beattached to the upper surface and the lower surface of the display panel100A.

In the present disclosure, the stereoscopic electrodes of theaforementioned electrode layer can also be formed into other shapes, asshown in FIG. 3A to FIG. 3C, which are schematic side views of theelectrode layer 120 in different embodiments.

As shown in FIG. 3A, in the electrode layer 120, the protrudingstructure 124 of the stereoscopic electrode 122 may be trapezoidal withrespect to the protective layer 118, and two separated electrode pads126 can be formed on each of the trapezoidal protruding structures 124.For two separated electrode pads 126 on each of the trapezoidalprotruding structures 124, different voltages, such as a positivevoltage and a negative voltage, can be applied thereto when the image isdisplayed on the display panel. As shown in FIG. 3B, in the electrodelayer 120, the electrode pad 126 of the stereoscopic electrode 122 canbe completely formed on the top surface of the protruding structure 124,that is, the electrode pad 126 does not extend to the sidewalls of theprotruding structure 124. For each pair of the adjacent electrode pads126, different voltages, such as a positive voltage and a negativevoltage, can be applied thereto when the image is displayed on thedisplay panel.

However, the present disclosure is not limited in this regard. In someembodiments, the electrode layer 120 can also omit the protrudingstructure, such that the electrode pad 126 is formed on a planar layer,as shown in FIG. 3C. For each pair of the adjacent electrode pads 126,different voltages, such as a positive voltage and a negative voltage,can be applied thereto when the image is displayed on the display panel.

Reference is made to FIG. 4 . FIG. 4 is a schematic side view of adisplay panel 100B according to a second embodiment of the presentdisclosure. At least one difference between the present embodiment andthe first embodiment is that the second substrate 150 of the presentembodiment is formed by curing a monomer which is added into the displaymedium layer 130, thereby omitting the assembling process.

Specifically, before curing, the second substrate 150 may be the monomerwhich is uniformly mixed in the display medium layer 130. After phaseseparation, the monomer can be suspended on the liquid surface of thedisplay medium layer 130. Next, after the monomer is cured, the secondsubstrate 150 is formed. Since the second substrate 150 is formed bycuring the liquid surface of the display medium layer 130, the curedsecond substrate 150 not only covers the spacer 140 and the displaymedium layer 130, but also at least a portion of the cured secondsubstrate 150 is disposed between the spacers 140. Such a configurationcan omit the disposition of an additional substrate, thereby improvingthe flexibility or the degree of flexibility of the display panel 1008.

References are made to FIG. 5A to FIG. 5D, which are schematic sideviews of the display panel 100B of FIG. 4 at different stages in themanufacturing process, respectively.

As shown in FIG. 5A, the transparent substrate 112, the array layer 114,and the color filter layer 116 of the first substrate 110 can be formedon the second carrier substrate 104 sequentially, and the protectivelayer 118 and the electrode layer 120 are formed on the color filterlayer 116 sequentially. These steps may be the same as the stagesillustrated in FIG. 2A, and will not be repeated hereinafter.

As shown in FIG. 5B, spacers 140 can be formed on the protective layer118, such that more than one accommodation space is defined on the firstsubstrate 110 by the spacers 140, in which the spacers 140 can be formedby performing the mask process or imprinting microstructures. Inaddition, although the spacers 140 are illustrated as bars standingupright on the protective layer 118 in the present embodiment, thepresent disclosure is not limited in this regard. In other embodiments,the spacers 140 of FIG. 5B can also be formed as the trapezoidal spacersas described above.

As shown in FIG. 5C, the filler 132, the liquid crystal capsule 134, thesurfactant 139, the photo initiator 160, and the monomer 162 can beuniformly mixed, such that the liquid crystal capsule 134 and thesurfactant 139, the photo initiator 160, and the monomer 162 can bedistributed in the filler 132 to form the display medium layer 130, inwhich the display medium layer 130 is filled in the accommodation spacedefined by the spacers 140, which can be achieved by one drop fill (ODF)manner.

Specifically, the photo initiator 160 may include oxyphenone,benzophenone, benzotriazole, boron carbazole derivative, phenylcarbazolederivative, 1-hydroxycyclohexylphenyl ketone, substance capable ofabsorbing infrared light, such as H-Nu-IR 780, H-Nu-IR 815, orcombinations thereof purchased from Spectra group limited incorporation,in which the chemical formula of H-Nu-IR 780 is

and the chemical formula of H-Nu-IR 815 is

However, the present disclosure is not limited in this regard. In otherembodiments, the photo initiator 160 may include substance capable ofabsorbing ultraviolet light, or combinations of substance capable ofabsorbing infrared light and substance capable of absorbing ultravioletlight. The substance capable of absorbing ultraviolet light may be, forexample, Ciba Product IRGANOX1 1076, IRGACURE 651, or combinationsthereof. In addition, the addition ratio of the light initiator 160 maybe from 0.1% to 1%. The ratio % in the aforementioned embodiment ispreferably taken a weight percentage (wt. %) as an example.

The monomer 162 may be a single acrylic functional group or amulti-acrylic functional group, such as an acrylic ester group or anacrylic methyl ester, in which the chemical formula of the acrylic estergroup is:

and the chemical formula of acrylic methyl ester is:

in which the “X” in the chemical formula can be a single bond, a triplebond, a double bond, or a bond such as —O—, —COO—, —OCO—, —O—CO—O—, or—CH₂O, the “Y” in the chemical formula may be a bond such as —(CH₂)_(n),and the value of n is an integer between 0 and 12, and the terminalgroup “R” in the chemical formula may be a polymerizable unit, such asacrylic acid, methacrylic acid, butylene oxide, vinyl epoxy, vinyl,vinyloxy, allyl ether, a bond such as —O—CO—CH═CH or styrene.

In addition to using the aforementioned chemical formula as the monomer162, a disk-shaped or a stick-shaped monomer 162 can also be used. Forexample, the disc-shaped monomer 162 may be hexayne benzene acrylicmolecule, hexamethylene methyl acrylic molecule, hexabenzoic acidacrylic molecule, hexaphenyl ether acrylic molecule or 2-naphthyl methylether acrylic molecule, for example, the chemical formula may be

where in the “X” in the chemical formula may be a single bond or such as—O—, —COO—, —OCO—, —C≡C—, —O—CO—O—, or —CH₂O, the “Y” in the chemicalformula can be a bond such as —(CH₂), and the value of n is an integerbetween 0 and 12, and the terminal group “R” in the chemical formula canbe a polymerizable unit, such as acrylic acid, methacrylic acid,butylene oxide, vinyl epoxy, vinyl, vinyloxy, propenyl ether, a bondsuch as —O—CO—CH═CH or styrene family. The stick-shaped monomer 162 maybe an acrylic acetylene benzoate, in which the chemical formula may be

in which the “X” in the chemical formula may be a single bond, a triplebond, a double bond, or such as —O—, —COO—, —OCO—, —O—CO—O—, or —CH₂O,the “Y” in the chemical formula can be a bond such as —(CH₂)_(n), inwhich the value of n is an integer between 0 and 12, and each of thevalues “m” and “p” in the chemical formula can be a positive integerbetween 1 and 12, the terminal group “R” in the chemical formula can bea polymerizable unit, such as acrylic acid, methacrylic acid, butyleneoxide, epoxy vinyl, vinyl, vinyloxy, propenyl ether, a bond such as—O—CO—CH═CH or styrenic group, and the terminal group “R” in thechemical formula may be hydrogen, halogen, an alkyl group having 1 to 20carbon atoms, or combinations thereof, and in the terminal group “R′”,at least one of —CH₂— may be replaced by a bond such as —O—, —S—,—CH═CH—, —CN, and the hydrogen thereof may be substituted with fluorine.Moreover, at this stage, the surfactant 139 can be added into thedisplay medium layer 130 such that the liquid crystal capsules 134 ofthe display medium layer 130 can be more uniformly mixed in the filler132.

As shown in FIG. 5D, the display medium layer 130 can be irradiated withlight 108 by using an irradiator 106, and the wave band of the light 108can be selected as infrared light band or ultraviolet light bandaccording to the characteristic of the light initiator (light initiator160 of FIG. 5C). After the display medium layer 130 is irradiated withthe light 108, the photo initiator (the photo initiators 160 and 162 inFIG. 5C) and the monomer can move to the liquid surface of the displaymedium layer 130 by their characteristics after the phase separation.Next, after the photo initiator is irradiated with the light 108 of thecorresponding wave band, it can react to form the second substrate 150.After the second substrate 150 is formed, the second carrier substrate104 can be detached from the first substrate 110 to obtain the displaypanel 100B as shown in FIG. 4 . In addition, after the display panel100B is obtained, the polarizers (not shown) can be attached to theupper surface and the lower surface of the display panel 1008.

In summary, the display panel of the present disclosure includes a firstsubstrate, an electrode layer, and a display medium layer, in which theelectrode layer is disposed on the first substrate and the displaymedium layer is disposed on the electrode layer. The display mediumlayer includes a filler and liquid crystal capsules, in which the liquidcrystal capsules are distributed in the filler, and the birefringencedifference Δn of the filler is in a range from 0.02 to 0.175. The fillerwith such a birefringence difference Δn can be achieved by adjusting itsmaterial configuration. By adjusting the birefringence difference Δn ofthe filler to be in a range from 0.02 to 0.175, the birefringencedifference Δn of the filler can be matched to the refractive index ofthe electrode layer, thereby avoiding light leakage of the display panelin a dark state so as to increase the contrast of the display panel.Moreover, the display panel of the present disclosure is flexible, andin a case where the display panel includes a configuration of colorfilter on array, the flexibility can further be enhanced.

While various embodiments of the present disclosure have been describedabove, it should be understood that they have been presented by way ofexample only, and not limitation. Numerous changes to the disclosedembodiments can be made in accordance with the disclosure herein withoutdeparting from the spirit or scope of the disclosure. Thus, the breadthand scope of the present disclosure should not be limited by any of theabove described embodiments. Rather, the scope of the disclosure shouldbe defined in accordance with the following claims and theirequivalents.

What is claimed is:
 1. A display panel, comprising: a first substrate;an electrode layer disposed on the first substrate; and a display mediumlayer disposed on the electrode layer, and comprising a filler and aplurality of liquid crystal capsules, wherein the liquid crystalcapsules are distributed in the filler, and a material of the filler atleast comprises at least one 1,4-cyclohexylene derivative, at least one1,4-phenyl derivative, at least one 1,3-indenyl derivative orcombinations thereof, wherein the chemical formula of 1,4-cyclohexylenederivative is

the chemical formula of 1,4-phenyl derivative is

and the chemical formula of 1,3-indenyl derivative is

wherein the electrode layer comprises a plurality of stereoscopicelectrodes, and each of the stereoscopic electrodes comprises aprotruding structure and an electrode pad, wherein the protrudingstructure protrudes from the first substrate toward the display mediumlayer, the electrode pad is disposed on the protruding structure, and athickness of the electrode pad is in a range from 300 nm to 700 nm. 2.The display panel of claim 1, wherein the display medium layer furthercomprises a surfactant uniformly mixed and distributed in the filler. 3.The display panel of claim 1, wherein the filler has a birefringencedifference Δn in a range from 0.02 to 0.175.
 4. The display panel ofclaim 1, further comprising a second substrate disposed on the displaymedium layer, wherein each of the first substrate and the secondsubstrate are flexible.
 5. The display panel of claim 4, furthercomprising a plurality of spacers disposed between the first substrateand the second substrate, wherein the second substrate is formed bycuring at least one monomer added into the display medium layer, and atleast a portion of the cured second substrate is disposed between thespacers.
 6. The display panel of claim 1, wherein each of the liquidcrystal capsules comprises a capsule film and at least one liquidcrystal molecule, and the capsule film covers the at least one liquidcrystal molecule, wherein the at least one liquid crystal molecule is arod-shaped structure or a disc-shaped structure.
 7. The display panel ofclaim 6, wherein the at least one liquid crystal molecule is thedisc-shaped structure, and the capsule film is an optical thermaladhesive formed of at least one monomer having a stick-shaped structure.8. The display panel of claim 1, wherein the first substrate comprises atransparent substrate, an array layer, and a color filter layer, thetransparent substrate is flexible, and the array layer is disposedbetween the transparent substrate and the color filter layer.
 9. Thedisplay panel of claim 1, wherein a short axial refractive index n⊥ ofthe filler is in a range from 1.45 to 1.5, and a long axial refractiveindex n∥ is in a range from 1.5 to 1.55.